U.S. patent application number 17/429549 was filed with the patent office on 2022-03-31 for absorbent article with embossed surface layer.
This patent application is currently assigned to Essity Hygiene and Health Aktiebolag. The applicant listed for this patent is Essity Hygiene and Health Aktiebolag. Invention is credited to Shabira ABBAS, Philip BLOMSTROM.
Application Number | 20220096282 17/429549 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-31 |
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United States Patent
Application |
20220096282 |
Kind Code |
A1 |
BLOMSTROM; Philip ; et
al. |
March 31, 2022 |
ABSORBENT ARTICLE WITH EMBOSSED SURFACE LAYER
Abstract
The absorbent article as disclosed herein has longitudinal side
edges extending in a longitudinal direction and transverse front
and rear end edges extending in a transverse direction. The
absorbent article including a fluid permeable surface layer and a
backsheet. The fluid permeable surface layer is an embossed surface
layer including an embossing pattern covering from 3% to 20% of the
total surface area of said surface layer. The surface layer is an
air-through-bonded fibrous nonwoven surface layer including
synthetic fibers and has a basis weight of from 14 to 30 g/m2.
Inventors: |
BLOMSTROM; Philip;
(Goteborg, SE) ; ABBAS; Shabira; (Goteborg,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Essity Hygiene and Health Aktiebolag |
Goteborg |
|
SE |
|
|
Assignee: |
Essity Hygiene and Health
Aktiebolag
Goteborg
SE
|
Appl. No.: |
17/429549 |
Filed: |
February 15, 2019 |
PCT Filed: |
February 15, 2019 |
PCT NO: |
PCT/SE2019/050131 |
371 Date: |
August 9, 2021 |
International
Class: |
A61F 13/511 20060101
A61F013/511 |
Claims
1. An absorbent article having longitudinal side edges extending in
a longitudinal direction and transverse front and rear end edges,
said absorbent article including a fluid permeable surface layer
and a backsheet, said fluid permeable surface layer being an
embossed fluid permeable surface layer including an embossing
pattern covering from 3% to 20% of the total surface area of a
wearer-facing portion of said surface layer, wherein said surface
layer is an air-through-bonded fibrous nonwoven surface layer
including synthetic fibers and having a basis weight of from 14 to
30 g/m.sup.2.
2. The absorbent article according to claim 1, wherein said
embossing pattern comprises embossed discontinuous dots having a
minimum diameter of 0.3 mm.
3. The absorbent article according to claim 1, wherein said
embossing pattern has a minimum depth of 0.3 mm.
4. The absorbent article according to claim 1, wherein said
synthetic fibers in said embossing pattern is permanently deformed
but not consolidated.
5. The absorbent article according to claim 1, wherein the nonwoven
surface layer comprising bicomponent fibers.
6. The absorbent article according to claim 1, wherein said
bi-component fibers are sheath-core bicomponent fibers, and wherein
said sheath is a polyethylene sheath.
7. The absorbent article according to claim 1, wherein said
bi-component fibers are sheath-core bicomponent fibers, and wherein
said core is a polyester core and said sheath is a polyethylene
sheath.
8. The absorbent article according to claim 1, wherein said
embossing pattern covering from 5% to 16% of the total surface area
of said wearer-facing portion of said surface layer.
9. The absorbent article according to claim 1, wherein said surface
layer has a density of from 20 to 90 kg/m.sup.3.
10. The absorbent article according to claim 1, wherein said fibers
of said air-through-bonded nonwoven have a coarseness of from 1.8
to 10 dtex.
11. The absorbent article according to claim 1, wherein said
surface layer is free from lotions and lubricating agents.
12. The absorbent article according to claim 1, wherein said
absorbent article comprises an intermediate layer located between
said surface layer and said backsheet.
13. The absorbent article according to claim 11, wherein said
intermediate layer covers from 70% to 100% of said surface
layer.
14. The absorbent article according to claim 11, wherein said
surface layer and said intermediate layer are adhesively attached
to each other.
15. The absorbent article according to claim 1, wherein said
absorbent article is a sanitary napkin.
16. The absorbent article according to claim 1, wherein said
embossing pattern comprises embossed continuous lines having a
minimum width of 0.3 mm.
17. The absorbent article according to claim 2, wherein said
embossing pattern further comprises embossed continuous lines
having a minimum width of 0.3 mm.
18. The absorbent article according to claim 1, wherein said
surface layer has a density of from 20 to 60 kg/m.sup.3.
Description
TECHNICAL FIELD
[0001] The present invention relates to an absorbent article. The
present invention in particular relates to an absorbent article
having a soft surface layer with an improved embossing pattern.
BACKGROUND OF THE INVENTION
[0002] Disposable absorbent articles, such as pantiliners, sanitary
napkins, adult incontinence devices and diapers, of the kind to
which this disclosure relates are worn against the skin and are
used to absorb bodily fluids. The absorbent articles include a
topsheet and a backsheet layer, and may also conventionally include
an absorbent core therebetween.
[0003] All uses of products which are applied in direct contact
with the skin sometimes experience skin problems. Skin problems can
be caused by forces arising from physical/mechanical interaction
between the absorbent product and the user's skin. Thus, for
example chafing is caused due to extra friction between the
absorbent product and the 20 skin of the user. The mechanical
friction between the material and the skin of the user is different
in the presence of liquid/moisture than when no liquid/moisture is
present.
[0004] Absorbent articles may have printed or embossed patterns
imposed upon their surfaces. For example, sanitary protection
articles, such as, napkins, pantiliners, and incontinence 25
devices, typically have a liquid permeable surface layer provided
with a pattern of depressed areas embossed into the surface in such
configurations as flowers or other feminine designs. Other patterns
may take the form of various geometric shapes, such as, circles,
diamonds, squares, curves, or other stylized figures, such as,
stars, spots, or the like.
[0005] While articles are embossed mainly for decorative purposes,
embossing may communicate or provide a function to the user of such
an article. For example, it is known that embossing functions in
impeding or directing fluid flow. Embossing is also done to provide
a visual cue to show differences in the material surface. To
provide the desired aesthetical effect, embossing patterns may
usually be imprinted relatively deep; e.g., the depressed areas may
be permanently depressed to a degree, which represents a major
portion of the thickness of the product.
[0006] It is an object of the present invention to provide an
absorbent article having a distinct embossing pattern as well as
having improved skin benefits.
SUMMARY OF THE INVENTION
[0007] One or more of the above objects may be achieved with an
absorbent article in accordance with claim 1. Further embodiments
are set out in the dependent claims, in the following description
and in the drawings.
[0008] The absorbent article as disclosed herein has longitudinal
side edges extending in a longitudinal direction and transverse
front and rear end edges extending in a transverse direction. The
absorbent article comprises a fluid permeable surface layer and a
backsheet. The fluid permeable surface layer is an embossed surface
layer comprising an embossing pattern covering from 3% to 20% of
the total surface area of a wearer-facing portion of said surface
layer. The surface layer is an air-through-bonded fibrous nonwoven
surface layer comprising synthetic fibers and has a basis weight of
from 14 to 30 g/m.sup.2.
[0009] The term "absorbent articles" refers to products that are
placed against the skin of the wearer to absorb and contain body
exudates, like urine, faeces and menstrual fluid. The disclosure
mainly refers to disposable absorbent articles, which means
articles that are not intended to be laundered or otherwise
restored or reused as an absorbent article.
[0010] Examples of disposable absorbent articles include feminine
hygiene products such as sanitary napkins and panty liners,
incontinence pads and diapers and the like.
[0011] The air-through-bonded fibrous nonwoven surface layer having
a basis weight of from 14 to 30 g/m.sup.2 has been found to enhance
the optical appearance of an embossing pattern by increasing the
distinctness of the embossing pattern. One reason may be that such
an air-through bonded fibrous nonwoven has relatively low number of
bonding points between the fibers within the material which
enhances the visibility of the embossing pattern when provided on
the material.
[0012] The synthetic fibers may be bicomponent fibers. The
bicomponent fibers may have a sheath of polyethylene or
polyprophylene. The core may be of polyester. To use synthetic
fibers in the air-through-bonded fibrous nonwoven wherein at least
the sheath of the fiber is of polyethylene has also been seen to
render the embossing pattern more distinct which may result from
breaking of the fiber structure during embossing.
[0013] To use synthetic fibers in the air-through-bonded fibrous
nonwoven wherein the sheath of the fiber is of polyester (PET) has
also been seen to render the surface material more resilient.
[0014] Air-through-bonded fibrous nonwoven material comprising
sheath-core bicomponent fibers, and particularly wherein the core
is a polyester core and the sheath is a polyethylene sheath, has
been seen to provide improved and distinct embossing patterns which
may result from breaking of the bicomponent fiber structure during
embossing and the polyester core is beneficial for enhancing the
resiliency of the nonwoven structure.
[0015] The fluid permeable surface layer is an embossed surface
layer comprising an embossing pattern covering from 3% to 20%, or
5% to 16%, of the total surface area of a wearer-facing portion of
said surface layer. This has been found to provide a soft and
compliant surface sheet with a good visibility of the embossed
elements. If a too large extent of the surface area of the surface
layer is provided with embossing pattern, the surface layer becomes
too stiff. The fluid permeable surface layer may have an embossing
free area in the crotch portion of the article corresponding to the
liquid inlet area so as to maintain a relatively low density (=high
bulk) in the liquid inlet area which is beneficial for the liquid
inlet rate.
[0016] By "wearer-facing portion" of the surface layer means the
portion of the surface layer facing the wearer during use of the
absorbent article. The absorbent article may for example comprise
wings or flaps provided with attachment means, such as adhesive.
The surface layer may extend over the wings of the absorbent
article, however the "wearer-facing portion" does not include wings
or flaps as these are not intended to face the wearer during use.
To determine the "wearer-facing portion" of the surface layer for
an absorbent article comprising wings or flaps, a straight line is
drawn between a starting point and an end point of the respective
wing along the respective longitudinal side of the absorbent
article, i.e. the start and end point being where the contour of
the absorbent article curve outwardly to form the respective
wings.
[0017] The embossing pattern may comprise embossed continuous
and/or discontinuous lines having a minimum width of 0.3 mm or 0.6
mm or 0.9 mm. The maximum width may be 5.0 mm, or 3.0 mm. The
discontinuous lines may comprise or consist of embossed dots
arranged in a discontinuous line, such as a straight or a curved
line and/or embossed pattern of different kind. The embossed dots
may have a minimum diameter of 0.3 mm, or 0.6 mm or 0.9. The
maximum diameter may be 5.0 mm, or 3.0 mm.
[0018] The embossing pattern may have a minimum depth of 0.3 mm,
0.4 mm or 0.5 mm. The maximum depth may be 3 mm.
[0019] The bi-component fibers in the embossing pattern may be
permanently deformed but not consolidated.
[0020] The surface layer may have a density of from 20 to 90
kg/m.sup.3, 20 to 60 kg/m.sup.3, 20 to 40, 15 to 40 kg/m.sup.3 or
20 to 30 kg/m.sup.3. The air-through-bonded surface layer has a
relatively low density, and this means that there is a relatively
high amount of void space between the fibres. The density can be
calculated by dividing the basis weight of the surface layer by its
thickness measured at a pressure of 0.5 kPa
[0021] The fibers of said air-through-bonded nonwoven surface layer
may have a coarseness of from 1.8 to 10 dtex, or 2 to 7 dtex or 3.5
to 7 dtex.
[0022] The surface layer may be free from lotions and/or
lubricating agents. As the surface layer in it-self has been found
to provide the surface layer with surprisingly low friction values
both under dry and wet conditions, lotions and lubricant agents may
not be needed to decrease the friction between the nonwoven and the
user's skin.
[0023] The surface material may be hydrophilic. A hydrophilic
material may be obtained by adding a surfactant.
[0024] The absorbent article may comprise an intermediate layer,
such as an intermediate 35 fibrous layer, located between the
surface layer and the backsheet and in direct contact with the
surface layer. The intermediate layer may be a nonwoven layer such
as airlaid or high-loft nonwoven materials, such as for example
air-through-bonded nonwoven or hydroentangled nonwoven
material.
[0025] The intermediate layer may extend under from 70% to 100% of
the wearer-facing portion of the surface layer.
[0026] The surface layer and the intermediate layer may be
adhesively attached to each other. This may increase the integrity
of the surface layer. The fact that the surface layer has a
relatively low density with relatively low number of bonding points
between the fibers gives a structure with lower integrity. However,
when combining the air-through-bonded fibrous nonwoven surface
layer with an intermediate layer having a lower elongation than the
air-through-bonded fibrous nonwoven, the air-through-bonded fibrous
nonwoven surface layer integrity is increased. Both during use of
the absorbent product as well as during manufacturing it is
advantageous that a structure(s) has a sufficient integrity.
[0027] It is also possible to attach the liquid surface material
with the intermediate layer by thermo- and or mechanical welding,
for example by ultrasonic welding. By this, the lamination and
embossing may be done in the same step.
[0028] According to one embodiment, only the fluid permeable
surface layer of the sanitary is embossed and not the intermediate
layer. However, according to another embodiment the embossing is
done also through the intermediate layer, so that also the
intermediate layer is embossed. Furthermore, it is also possible to
emboss through the surface layer, the intermediate layer and also
through a further layer such as for example an absorbent core which
may be arranged between the intermediate layer and a backsheet. If
the liquid surface material is laminated together with the
intermediate layer through thermo- and or mechanical welding, the
lamination and embossing may be done in the same step. One
embossment may penetrate both the fluid permeable surface layer and
the intermediate layer, for example by ultrasonic welding.
[0029] The backsheet has a garment facing side and an adhesive may
be arranged on said garment facing side.
[0030] The absorbent article may include an absorbent core arranged
between the surface layer and the backsheet and between the
intermediate layer and the backsheet if the absorbent article
comprises an intermediate layer. The absorbent core may for example
include pulp fibers or may comprise a mixture of superabsorbent
particles and pulp fibers.
[0031] The backsheet may be a breathable or non-breathable plastic
film. The backsheet may be a polyolefin plastic film. The backsheet
may also be a laminate of a plastic film and a nonwoven
material.
[0032] The absorbent article may be a sanitary napkin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The present invention will be further explained hereinafter
by means of non-limiting examples and with reference to the
appended drawings wherein:
[0034] FIG. 1 shows a top plan view of a sanitary napkin as
disclosed herein and as seen from a topsheet side; and
[0035] FIG. 2 shows an exploded perspective view the sanitary
napkin of FIG. 1.
[0036] FIG. 3a shows enlarged photographs of surface materials
comprising discontinuous embossing dots;
[0037] FIG. 3b shows enlarged photographs of surface materials
comprising embossing continuous lines;
[0038] FIG. 4 shows friction measurement result on surface
materials.
DETAILED DESCRIPTION
[0039] The invention will be described more closely below by
reference to an exemplary embodiment. The invention may however be
embodied in many different forms and should not be construed as
limited to the embodiments set forth in the drawings and the
description thereto.
[0040] FIG. 1 is a top plan view of a sanitary article 1 having
longitudinal side edges 2,3 extending in a longitudinal direction L
and transverse front and rear end edges 4,5 extending in a
transverse direction T. The sanitary article 1 comprising a fluid
permeable surface layer 8 and a backsheet 9. The surface layer 8 is
an air-through-bonded fibrous nonwoven surface layer having a basis
weight of from 14 to 30 g/m.sup.2. The nonwoven layer comprises
bicomponent fibers and may constitute of from 50% or more, such as
80% to 100% or from 95% or more, of bicomponent fibers. The
bicomponent fibers may be sheath-core bicomponent fibers, for
example the core is a polyester core and the sheath is a
polyethylene sheath.
[0041] The fluid permeable surface layer 8 comprises an embossed
pattern 11. The embossed pattern 11 comprises individual embossed
elements 11a in the form of dots forming a pattern covering from 3%
to 20% of the wearer-facing portion of the surface layer 8. At a
rear end 12 of the absorbent article 1, the surface layer 8 is
provided with an embossed wing-shaped continuous line 11b and a
continuous embossed line extends along a contour of the absorbent
article 1 framing the embossed pattern 11.
[0042] The absorbent article 1 in FIG. 1 is a sanitary napkin and
is provided with a pair of lateral wings 13 extending outward from
the transversely opposite side edges 2,3 of the napkin. The wings
are provided with attachment means, such as with an adhesive, on
their garment facing surface so that the wings 13 can be folded
back under the undergarment and attached to the undergarment. In
this way, the wings 13 serve to keep the napkin 1 properly
positioned in the undergarment.
[0043] FIG. 2 is an exploded view of the sanitary napkin 1 shown in
FIG. 2 and illustrates the sanitary napkin with the layer of the
sanitary napkin 1 separated. The sanitary napkin 1 comprises a
fluid permeable surface layer 8 and a backsheet 9. An intermediate
fibrous layer 10 is located between the surface layer 8 and the
backsheet 9 and in direct contact with the surface layer 8. In this
figure the intermediate layer is provided under about 100% of the
total surface area of a wearer-facing portion of the surface layer
8 and is adhesively attached to the surface layer 8. An absorbent
core 14 is arranged between the intermediate layer 10 and the
backsheet 9. Only the fluid permeable surface layer 8 of the
sanitary napkin 1 in FIG. 2 is embossed and not the intermediate
layer 10. However, also the intermediate layer may be embossed, and
the embossing may be done in one step so that the embossments are
penetrating both the fluid permeable surface layer 8 and the
intermediate layer 10 in the same embossing step. It is also
possible to laminate the liquid surface material 8 together with
the intermediate layer 10 through thermo- and or mechanical
welding, for example by ultrasonic welding. By this, the lamination
and embossing are done in the same step.
[0044] The backsheet may be a breathable or non-breathable plastic
film. The backsheet may be a laminate of a breathable or
non-breathable plastic film and a nonwoven material.
[0045] The absorbent core may be of any conventional kind. Examples
of commonly occurring absorbent materials are cellulosic fluff
pulp, tissue layers, highly absorbent polymers (so called
superabsorbents), absorbent foam materials, absorbent nonwoven
materials or the like. It is common to combine cellulosic fluff
pulp with superabsorbents in an absorbent structure. It is also
common to have absorbent structures comprising layers of different
material with different properties with respect to liquid
acquisition capacity, liquid distribution capacity and storage
capacity. This is well-known to the person skilled in the art and
does therefore not have to be described in detail. The thin
absorbent bodies, which are common in today's sanitary articles,
often comprise a compressed mixed or layered structure of
cellulosic fluff pulp and superabsorbent. The size and absorbent
capacity of the absorbent structure may be varied to be suited for
different uses such as sanitary articles, pantyliners, adult
incontinence pads and diapers, baby diapers, pant diapers, etc.
[0046] The intermediate layer may be composed of for example
airlaid nonwoven, high loft nonwoven such as for example
air-through bonded nonwoven or hydroentangled nonwoven. An air laid
nonwoven can be produced with fluff, wood pulp, and here the fluff
fibres are dispersed into a fast-moving air stream and condensed
onto a moving screen by means of pressure and vacuum. The web can
be bonded with resin and/or thermal plastic resin dispersed within
the pulp. The web can be thermobonded (by heat), latex bonded (with
adhesive) or multibonded (a combination of thermo and latex
bonding) or mechanically bonded (high compression and temperature,
bonding by hydrogen). The grammage of the airlaid nonwoven can
suitably be from 50 to 100 gsm.
[0047] High loft is a nonwoven material and may be substantially
free from absorbing fibres and superabsorbent material. The high
loft nonwoven material may comprise thermoplastic polymer fibres,
and may be selected from but not limited to, polyesters, polyamides
and polyolefins such as polyethylenes (PE) and polypropylenes (PP),
and may be a mixture of any of these. The "high loft" refers to low
density bulky fabrics, as compared to flat, paper-like fabrics.
High loft webs are characterized by a relatively low density. This
means that there is a relatively high amount of void space between
the fibres. The intermediate high loft nonwoven layer may typically
have a density below 200 kg/m.sup.3, in particular ranging from 15
kg/m.sup.3 to 150 kg/m.sup.3, in particular from 30 to 100
kg/m.sup.3. The average density can be calculated by dividing the
basis weight of the high loft layer by its thickness measured at a
pressure of 0.5 kPa. Normally the thickness of the intermediate
layer of high loft material is more than about 0.5 mm, such as more
than 1 mm or suitably 1.5-2.0 mm, and the solid content is low,
usually less than 15% by volume.
[0048] The raw material for the intermediate layer may be
polyolefines, for example be polypropylene (PP), polyethylene (PE),
or polyester (PET), polyamide (PA), cellulosic fibres or a
combination of these. Thus, if a combination of different fibres is
used, this can be a mixture of fibres from different polymers,
although each fibre can also include different polymers (e.g. PP/PE
bi-component fibres or PP/PE copolymers).
[0049] Where appropriate, the plastic backsheet film may comprising
PE or PP, PET, PLA or amyl (or, for that matter, any other
thermoplastic polymer), or a mixture or copolymers of the
aforementioned polymers.
[0050] In FIG. 4 shows the friction curves for test sample, CEx 1
and CEx2. In FIG. 4 is the number of runs on the x-axis and the
friction force in gmf on the y-axis. A friction curve comprises a
first slope having a positive coefficient illustrating increase in
the friction values, a plateau, and a second slope having a
negative coefficient illustrating decrease in friction values. At
the plateau, the friction values are substantially constant over
the extension of the plateau. Small variations at the plateau as
well as along the slopes are possible between individual values,
but with a positive coefficient is meant that all individual values
in the first slope together creates a positive coefficient, as well
as all individual values in the second slope together creates a
negative coefficient, as well as all individual values in the
plateau together creates a plateau. Lower friction values render
the absorbent article more skin friendly and skin problems arising
with the use of the absorbent article can be reduced. For some
materials a clear peak can be seen in a curve of friction values
before the second slope creating a negative coefficient. Such a
peak is caused by clinging, which may occur when only a small
amount of moisture is present. The result in FIG. 4 shows that the
test sample, the air-through-bonded nonwoven surface material, has
a lower mean friction plateau value (gmf).
[0051] Embossing Measurement
[0052] The depth of the individual embossed elements in the form of
dots have been measured by the method ISO25178 and also the depth
of a continuous embossed line extending along a contour of the
absorbent sanitary napkin framing the embossed pattern comprising
the individual embossed elements have been measured by the method
ISO25178.
[0053] Three different sanitary napkins were tested having
different surface layers but otherwise constructed with the same
underlying materials and compared in terms of diversity of
embossment depth. The test material is an air-through-bonded
nonwoven according to the present disclosure comprising bicomponent
fibers of core-sheath type with a polyester core and a polyethylene
sheath. The first Comparative Example is a spunbond nonwoven with
polypropylene fibers and the second Comparative Example is spunbond
nonwoven with polypropylene fibers. Table 1 below provides
specifications of the materials tested.
TABLE-US-00001 TABLE 1 Basis weight Material Type Supplier Material
no (gsm) Test sample Air-though TWE 255272 20 bonded nw CEx 1
Spunbond Texbond 2436701 18 nonwoven CEx 2 Spunbond Union 272119 18
nonwoven
[0054] In Table 2 shows the result of the mean individual depth of
the individual embossed elements (.mu.m) and the standard deviation
of the depth (.mu.m).
TABLE-US-00002 TABLE 2 Mean individual depth (.mu.m) Standard
deviation (.mu.m) Test sample 388 5.9 CEx 1 446 26.0 Cex 2 368
22.3
[0055] The result shows that the standard deviation of the depth
value of the embossment element for the air-through-bonded
nonwoven. The standard depth deviation for the Test sample was
lower than the standard depth deviation for the comparative example
1 (Cex 1) and the comparative example 2 (Cex 2).
TABLE-US-00003 TABLE 3 The depth of a continuous embossed line, a
"valley" Ratio between Mean Standard Standard deviation individual
deviation and Mean individual depth (.mu.m) (.mu.m) depth Test
sample 971 148 0.15 CEx 1 597 204 0.34 Cex 2 442 91 0.21
[0056] The mean individual depth of a continuous embossed line, a
"valley", for the air-through-bonded nonwoven according to the Test
sample, as seen in table 3, has a lower ratio between Standard
deviation and Mean individual depth than the Comparative example 1
(Cex 1) and the Comparative example 2 (Cex 2).
[0057] So, both the standard deviation of the mean depth of the
individual embossed elements in the form of dots, and the ratio
between Standard deviation and Mean individual depth of a
continuous embossed line extending along a contour of the absorbent
sanitary napkin framing the embossed pattern comprising the
individual embossed elements shows that the air-through-bonded
nonwoven surface material has more distinct embossed elements that
enhances the visibility of the embossing pattern when provided on
the material.
[0058] Also, the enlarged photos in FIGS. 3a and 3b shows that the
sanitary napkin with the test sample (air-through-bonded nonwoven)
as surface material has more distinct embossed elements that
enhances the visibility of the embossing pattern than the
Comparative example 1 (Cex 1) and the Comparative example 2 (Cex
2).
[0059] Friction Measurement
[0060] Friction occurring between a nonwoven material and the skin
of the user is different in the presence of liquid/moisture than
when no liquid/moisture is present. Even a very small amount of
moisture present originating from perspiration, sweat or other body
fluids has an impact on the friction forces occurred between the
nonwoven material and the skin of the user. It has therefore been
discovered that it is really important to carefully choose the
nonwoven characteristics, so that the nonwoven is able to minimize
the mechanical discomfort during the overall use of the
product.
[0061] The method used for the friction measurement was the Stick
and slip measurement method which is described in detail in WO
2016/114693. The friction measurement has been performed according
to the description in WO 2016/114693.
[0062] The method measures the static friction, sns value (stick
and slip value) in gram force, gmf, between a material and the
human skin. The method means that repeatedly runs are made using
the same material strip. First the sns value for the dry state (dry
material and skin) is measured followed by wet state at different
liquid levels (from completely wetted material, to moist and to
almost dry) until the sns value is back to the skin-material
interaction level measured in the first dry run, which mean that
the material is dry again.
[0063] The method is thus called a repeated stick and slip method
or sns dry-wet-dry. The stick and slip value is defined as the
point on the force curve (gmf) where the material starts gliding
over the arm. The sns values from all single force curves are then
put together in a new graph, sns values as a function of number of
runs.
[0064] Three different nonwoven materials were tested and compared
in terms of dry friction and wet friction. The test material is an
air-through-bonded nonwoven according to the present disclosure
comprising bicomponent fibers of core-sheath type with a polyester
core and a polyethylene sheath. The first Comparative Example is a
spunbond nonwoven with polypropylene fibers and the second
Comparative Example is spunbond nonwoven with polypropylene fibers.
Table 1 above provides specifications of the materials tested.
[0065] In table 4 below shows result of the mean friction plateau
values measured in gmf. By gmf is meant gram-force and one
gram-force is 9.80665 mN and the result shows that the test sample,
the air-through-bonded nonwoven surface material has a lower mean
friction plateau value (gmf).
TABLE-US-00004 TABLE 4 Material Mean friction plateau value, (gmf)
Test sample 300 CEx 1 480 CEx 2 420
[0066] Also in FIG. 4 shows the friction curves for test sample,
CEx 1 and CEx2 and the result shows that the test sample, the
air-through-bonded nonwoven surface material, has a lower mean
friction plateau value (gmf).
[0067] Density Measurement
[0068] The density is calculated by dividing the basis weight of
the surface layer by its thickness. The thickness is determined by
means of a measuring foot with affixed load of 0.5 k Pa. The
measuring foot has an area of 50.times.50 mm.sup.2. The thickness
is read off at the digital thickness gauge/tester after 10 seconds
when the measuring foot has touched the surface of the sample.
* * * * *